A sortable acidity reference for organic chemistry — acid classes with their pKa, the conjugate base each forms, and what stabilizes it — plus leaving-group ability and nucleophilicity trends.
Sortable pKa table spanning the full acidity range
Conjugate bases and the factors (resonance, induction, hybridization) that stabilize them
Leaving-group ability tied to conjugate-acid pKa
Nucleophilicity trends for predicting substitution and elimination